In a fabrication of semiconductor devices, IC designs and resulting devices may need to support p-type and n-type devices having multi Vth. Typical methods for forming multi Vth devices include depositing, patterning, etching, removing and re-depositing titanium nitride (TiN) multiple times. However, this process is highly complex, and results in damage at the TiN and high-k dielectric interface, since the TiN is etched all the way down to the high-k dielectric layer, thereby exposing the high-k dielectric layer to the etchants.
A need therefore exists for methodology enabling formation of plural TiN thicknesses without damaging an underlying high-k dielectric layer and the resulting device.